Test Procedure for the LV8712TGEVB Evaluation Board For Stepper Motor Control CURRENT PROBE AMPLIFIER 1 Osclloscope CURRENT PROBE AMPLIFIER 2 PROBE INPUT PROBE INPUT OUTPUT OUTPUT CHANNEL 4 3 2 1 Stepping Motor Power supply 1 V A Multimeter - + VOUT - + Power supply 2 A V Power supply 3 A V - - + + Function generator Hz CHANNEL 1 2 Table1: Required Equipment Equipment Power supply1 Power supply2 Power supply3 Function generator Multimeter Oscilloscope Current probe1 Current probe2 LV8712T Evaluation Board Stepper Motor 1/8/2014 1 Efficiency 10V-1A 5V-0.5A 20V-2A 50kHz 4 channel 20V-1A www.onsemi.com Test Procedure: 1. Connect the test setup as shown above. 2. Set it according to the following specifications. Supply Voltage • • • VM (4 to 16V) : Motor Power Supply VCC (2.7 to 5.5V) : Control Power Supply VREF (0 to VCC-1.8V) : Const. Current Control for Reference Voltage Toggle Switch State • • • Upper Side: High (VCC) Middle: Open, enable to external logic input Lower Side: Low (GND) Operations Guide 1. Initial Condition Setting: Set “Open or Low” all switches. 2. Motor Connection: Connect the Motors between OUT1A and OUT1B, between OUT2A and OUT2B. 3. Power Supply: Supply DC voltage to VCC, VM and VREF. 4. Ready for Operation from Standby State: Turn “High” the PS pin toggle switch. Channel 1 and 2 are into full-step excitement initial position (100%, 100%) . 5. Motor Operation: Turn “High” the RST pin toggle switch. Input the clock signal into the STEP pin. 6. Other Setting: (See Application Note for detail) i. ATT1, ATT2: Motor current attenuation. ii. FR: Motor rotation direction (CW / CCW) setting. iii. MD1, MD2: Microstep Resolution. iv. OE: Output Enable. Setting for External Component Value 1. Constant Current (100%) At VREF = 1.0V Iout = VREF [V]/5/RNF [ohm] =1.0 [V] / 5 / 0.47 [ohm] =0.426 [A] 2. Chopping Frequency Fchop =Ichop [uA]/(Cchop x Vt x 2) =10 [uA] / (180 [pF] x 0.5 [V] x 2) =55 [kHz] 3. Check REG5 pin voltage at multimeter. 4. Check the STEP and MONI pin voltage at scope CH1 and CH2, and the output current 1/8/2014 2 www.onsemi.com waveform at scope CH3 and CH4. Table2: Desired Results INPUT OUTPUT VM=12V VREF=1.0V VCC=5V REG5=4.5V to PS=High 5.5V RST=High ATT1=ATT2=FR=OE=Low 5. Oscilloscope Waveform Figure 1. Full-step (MD1=MD2=Low, fSTEP=500Hz) fSTEP=1kHz) Figure 2. Half-step (MD1=High,MD2=Low, 2ms/div 2ms/div STEP 5V/div STEP 5V/div MONI 5V/div MONI 5V/div Iout1 0.2A/div Iout1 0.2A/div Iout2 0.2A/div Iout2 0.2A/div Figure 3. Quarter-step (MD1=Low,MD2=High, fSTEP=2kHz) fSTEP=4kHz) 2ms/div 1/8/2014 Figure 4. 1/8-step(MD1=MD2=High, 2ms/div STEP 5V/div STEP 5V/div MONI 5V/div MONI 5V/div Iout1 0.2A/div Iout1 0.2A/div Iout2 0.2A/div Iout2 0.2A/div 3 www.onsemi.com